This invention relates to an electrostatic-recording gas discharge device for use in an electronic printing device, a facsimile receiver, and the like.
A phenomenon is known as an ionization-coupling action, in which the application of a voltage between two electrodes placed in a gas causes a gas discharge therebetween, then the firing voltage is lowered for another two electrodes placed in the close vicinity of the former two electrodes. A discharge tube is also known, which includes a plurality of cathodes (scanning electrodes) connected to each other in a suitable manner and an anode (an opposing electrode) opposed thereto, and in which a discharge is successively shifted in a given direction from one scanning electrode to another in response to electric pulse signals due to the aforesaid phenomenon.
This discharge tube has as its principal applications a discharge counter tube adapted to count pulse signals and a display device utilizing a glow discharge.
The electrostatic recording device utilizing the aforesaid phenomenon is proposed by Toshio Ohkubo and others in U.S. Pat. No. 3,750,190 and U.S. Pat. No 3,870,257. These proposals are based on the shift of discharge from one scanning-opposing electrode pair to another caused by the change in gas conductivity. Thus, in case a plurality of electrodes termed as voltage inducing electrodes are arranged in respective discharge spaces, then potentials in the spaces are successively induced at the electrodes.
Potentials at the voltage inducing electrodes are several hundred volts higher than the scanning electrode potential, so that connections of recording stylus electrodes to the respective voltage inducing electrodes bring about scanning pulse output voltages of several hundred volts. Thus, the scanning-pulse-output voltage is then applied to a dielectric layer on an electrostatic recording medium contiguous to the recording stylus electrodes, while a negative video signal voltage is applied to the back surface of the recording medium, thereby achieving the desired recording.
However, this electrostatic recording device suffers from a disadvantage that if there is a defect in the dielectric layer on the electrostatic recording medium, then a negative video signal voltage will be applied to the voltage inducing electrodes through the recording stylus electrodes, with the result that a detrimental discharge is caused between the voltage inducing electrodes and the opposing electrode, and consequently scanning is disturbed.